The study was conducted in two private high schools in district Gilgit of Gilgit-Baltistan to find out headteachers? perceptions and practices about school improvement, their leadership strategies to lead the school improvement initiatives and also the challenges they face to this end. I used a qualitative paradigm with an interpretivist epistemology. Semi-structured interviews, document analysis/review, focused group discussion/interview and participant observations were used as tools for data collection to triangulate the findings. Researcher adopted a thematic approach to data analysis, which helped me to identify the major themes and then to add the sub-themes from across the data. The findings show that the headteachers perceive school improvement as a sustained data-driven process to improve the schools? academic, administrative affairs and the holistic development of the children. To this end, they applied various strategies starting from developing a joint purpose for school improvement to leading the schools by examples, effective school development plan, capacity building of teachers, regular assessment of students? learning, headteachers? instructional role, parental involvement and changes in school culture and effective monitoring of the schools? affairs, which are equally workable in all context and thus seemed universal in their application for school improvement. The study, however, also found that school improvement initiatives are not like swimming in placid water rather than it is a complex process and therefore, the head teachers face lots of challenges such as, teachers? retention, uncooperative parents, absence of teachers? induction programme, poor economy of parents and lack of residential facilities for non-local teachers. The findings of the study confirmed most of the school improvement studies carried out in Pakistan and abroad. However, two of the findings of this study, i.e., (a) Child holistic development as one of the important elements of school improvement and (b) the headteachers? sustained monitoring mechanisms of school improvement seen value addition to the research studies about School Improvement.